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<h2>About</h2>
<p><i>Padb</i> is a <b>Job Inspection Tool</b> for examining and debugging
parallel programs, primarily it simplifies the process of gathering stack traces
on compute clusters however it also supports a wide range of other functions.
<i>Padb</i> supports a number of parallel environments and it works
out-of-the-box on the majority of clusters. It's an open source,
non-interactive, command line, script-able tool intended for use by programmers
and system administrators alike.</p>

<p>
<i>Padb</i> is developed and maintained by
<a href="mailto:ashley@pittman.co.uk">Ashley Pittman</a>.</p>

<table class="news" width="70%" cellspacing="0" cellpadding="5" border="1" align="center">
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<h2 align="center"><a name="news">Recent News</a></h2>

<ul>
 <li><font size="+2"><b>08-12-10</b>: 3.3 release avaliable for
 <a href="download.html">download</a>.  It is recommended all
 users upgrade to version 3.3.</font>

 <li><b>23-10-10</b>: 3.2-beta1 avaliable for
 <a href="download.html">download</a>.

 <li><b>06-10-09</b>: 3.0 release avaliable for
 <a href="download.html">download</a>.
 <li><b>15-09-09</b>: 3.0-rc2 avaliable for download.
 <li><b>01-09-09</b>: A 3.0-rc release is avaliable to download from
 the <a href="download.html">downloads page</a>.
 <li><b>25-06-09</b>: A 2.5 stable release (version 2.5) is avaliable to
 download from the <a href="download.html">downloads page</a>.
</ul>
</td></tr>
</table>

<h2>Features</h2> The following <a href="modes.html">modes</a> of operation are
supported:
<ul>
<li>Stack trace generation</li>
<li>MPI Message queue display</li>
<li>Deadlock detection and collective state reporting</li>
<li>Process interrogation</li>
<li>Signal forwarding/delivery</li>
<li>MPI collective reporting</li>
<li>Job monitoring</li>
</ul>

<h2>What padb can't do</h2>
<i>Padb</i> is a job inspection tool, it can tell you want you want to know
about your job and your MPI stack, it will not, however, tell you about your
cluster as a whole and it won't diagnose problems with your wider environment,
including you job launcher or runtime environment. <i>Padb</i> does not launch
or wrap your jobs for you, it is not a job harness but rather attaches to or
targets jobs which are already running.

<h2>License</h2>
<i>padb</i> is licensed under the
<a href="http://www.gnu.org/licenses/lgpl.html">LGPL</a> and as such is
open-source and free to use and modify.

<h2>History</h2>
<i>Padb</i> was originally conceived by software developers at
<a href="http://www.quadrics.com/">Quadrics</a> around 2004 to solve the kind of
problems facing them at the time. It's been a part of the Quadrics software
stack for a number of years and has recently been made available to a wider
audience. It has been commercially supported for a number of years and is known
to work at a scale of tens of thousands of processes.

<h2>Parallel Environments</h2>
<i>Padb</i> works and is supported on the following parallel environments and
MPI stacks. Not all features are available on all runtimes.
<ul>
<li><a href="http://www.quadrics.com/">Quadrics RMS</a><br>Runs natively on
clusters running RMS.</li>
<li><a href="https://computing.llnl.gov/linux/slurm">Slurm</a><br>Runs
natively on clusters running Slurm irrespective of the runtime used.</li>
<li><a href="http://www.open-mpi.org/">Open MPI</a><br>Supports orte or
OpenMPI jobs run under slurm.</li>
<li><a href="http://www.mcs.anl.gov/mpi/mpich/">MPICH2</a><br>Supports mpd or
MPICH2 jobs run under slurm.</li>
</ul>
<p>In addition padb can be told to target individual UNIX processes.

<h2>Prerequisites</h2>
<i>Padb</i> requires very little support from the OS or parallel environment to
run, it's main use is to assist in the debugging of parallel applications, it's
therefore assumed that you have a working MPI stack or other parallel
environment and that "Hello world" application runs to completion without
error.<br>

A <i>Linux</i> operating system is assumed and a working <i>gdb</i> is required
for stack trace functionality.  Work on a <i>solaris</i> port is under way.
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 <p>Page maintained by Ashley Pittman. $Date: 2010-12-08 23:56:56 +0000 (Wed, 08 Dec 2010) $ $Revision: 428 $</p>
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